Severe Weather.... --Tornadoes & Hurricanes
Tornadoes....
- • Tornadoes are the most violent storms on the surface of the Earth.
- • 70% of all tornadoes on Earth occur in the Great Plains region of the United States.
Tornadoes....
- • Air masses collide over tornado alley, causing rotation:
- • Warm, moist air masses from the Gulf of Mexico
- • fast-moving polar air masses from Canadian Rockies.
Tornadoes....
- • Common in the late spring and early summer
- • Low pressure systems, as are all storms
- • Cause a lot of damage yet the majority average 200 meters in diameter & last less than 10 minutes.
Tornadoes....
Hurricanes....
Hurricanes....
•Largest storms on Earth & the only storms which are named.
•Different parts of the world have different names:
United States: Hurricanes
Indian Ocean: Cyclones
Western Pacific (Japan): Typhoons
Requirements for a hurricane:
•Water temperature has to be at least 80°F in the
upper 200 feet of water
•Air Must be both warm & humid
•Form in 5° to 20° latitude
FormaEon of Hurricanes:
- • Warm water in the equatorial region needs to transfer energy
- • Does so by evaporating water molecules into the atmosphere (water cycle)
- • Winds start forming--
**Counterclockwise in Northern Hemisphere
**Clockwise in the Southern Hemisphere
(Due to Coreolis Effect)
Wind Speed
•Winds under 39 mph
•Winds 39-74 mph
•Winds over 74 mph
Storm Type
**Tropical Depression
**Tropical Storm
**Hurricane
Hurricanes....
- • Hurricane will strengthen as long as it is over warm water!
- • Once hurricane reaches land it weakens because there is no more heat energy from the warm water to fuel it!
Hurricane Damage....
90% of all deaths occur in the storm surge!